Roller core breaker for bits



Dec. 17, 1935.

o. HAMMER ROLLER CORE BREAKER FOR BITS Filed Sept. 17, 1954 OHOmmer @WwmPatented Dec. 17, 1935 UNITED STATES ROLLER CORE BREAKER FOR BITS OttoHammer, Whittier, Calif., assignor to Sccurity Investment Company,Whittier, Calif., a corporation of California Application September 17,1934, Serial No. 744,325

9 Claims.

This invention relates to a roller type core breaker for bits, such aswell drilling bits.

Heretofore, core type bits have been designed which cut the formationaround a central core and in the case of core barrels provision is madefor breaking off and removing the core. Other types of bits have beendesigned which cut the formation wherein the bit is rotated about avertical, central axis as in the conventional rotary well drillingpractice but in such types of bits there is usually no satisfactoryprovision made for breaking up the core which is left at the center ofthe well hole. In such types of bits, in hard drilling, the core whichremains causes the bit to merely ride on the core, hindering furtherprogress downwardly into the formation.

An object of the present invention is to provide a roller type corebreaker for well drilling bits which may be applied to various styles ofbits and which is particularly designed for use on core type bits,enabling the advantages of a core bit to be retained and simultaneouslyand effectively breaking up the core as it is formed, thus reservingcore barrels for use only where it is desired to recover a core forgeological study.

A further object of the invention is to provide a core breaker for bitsof the roller type so that the advantages of a roller in presenting alarge amount of cutting edge over which the wear may be distributed arepresent.

A further object of the invention isto provide a core breaker for bitswhich is of such design as to have a distributed bearing against thecore while breaking up the core so as to thus be'eifective to stabilizethe bit during its rotation.

Still a further object of the invention is to provide a roller type corebreaker for bits of rigid, simple, and durable design which willefliciently break up the core and which, when the rollers have becomebadly worn from continued use, can have the rollers easily and quicklyreplaced.

With the foregoing and other objects in view, which will be mademanifest in the following detailed description, and specifically pointedout in the appended claims, reference is had to the accompanying drawingfor an illustrative embodiment of the invention, wherein:

Fig. 1 is a vertical section through a well drilling bit illustratingthe invention as having been embodied thereon.

Fig. 2 is a bottom plan view taken upon the line 2-2 upon Fig. 1 in thedirection indicated.

Fig. 3 is a horizontal section taken upon the line 3-3 upon Fig. 1 inthe direction indicated. Referring to the accompanying drawing, whereinsimilar reference characters designate similar parts throughout, the bitin which the invention has been embodied is shown as consist- 3 ing of abody ill attachable such as by a sub II to a drill pipe' l2. This bodyhas an enlarged interior 13 for circulation fluid which passes therefromthrough ports or passages 54 leading to the bottom of the body. On thebottom of the body 10 there are formed cutting blades and in the presentinstance I have illustrated the blades as consisting of three largeblades l5 and three small blades It. The large blades l5 projectoutwardly beyond the sides of the body and serve to ream the walls ofthe well and keep it out to gage as well as to cut the formation. Thesmall blades serve merely as cutters and the inner ends of all of theblades project inwardly beyond the sides of a hollow dome-shaped recessll formed in the bottom of the body. The inner ends of the blades definethe size of the core cut by the bit. The particular design of thecutting blades l5 and I6 is immaterial insofar as the present inventionis concerned and may be varied considerably. These are mentioned forillustrative purposes onlyvto lay the setting for the location of thepresent invention. The core breaker for breaking up the core, indicatedby dotted lines at C on Fig. 1, consists of rollers I8 and I9 disposedwithin recess [1. A diametrical web 20 extends across the recessadjacent its top and pins 2| and 22 extend from the bottom edge of thebody up into this diametrical web. These pins are so arranged as to beupwardly and inwardly inclined but they are disposed otherwise than inradial planes of the bit. In the preferred form of invention whereinthere are two rollers and pins therefor, the pins are in parallel planeson opposite sides of a diameter of the bit. Preferably, the upper endsof the pins are provided with bushings 23 disposed in web 20 and in asimilar manner the lower ends of the pins of the bushings which fit inthe recesses therefor formed in the sides of recess H. The holes for theinsertion of the pins are indicated at 24 and 25 on the bottom serviceof the body and are preferably closed by screw plugs 26. The rollers arerotatable on the pins between the bushings. The rollers l8 and I9 areprovided with circumferentially extending teeth and these teeth may beeither a series of annular ridges or they may progress from one end ofthe roller to the other similar to threads. In the preferred form ofconstruction each roller is 01' general hyperboloidal shape. The reasonfor giving the roller cutters this general shape is to cause them, dueto the arrangement oi. their respective axes, to scarity the core C sothat its top will be truly conical. Each tooth, along the length of therollers, will be caused to do its proper share oi cutting on the core.While in certain instances the general shape of each roller may be trulycylindrical when the rollers are so designed, due to the positions ofthe axes about which the rollers rotate, the top of the core would notbe cut or scariiled into a true cone but, instead, its sides instead ofbeing straight would be I slightly concave, resulting in the centerteeth being subjected to the greatest wear. It will be noted that therollers bearing on the sides of the cone on the top of the core in anoblique direction form a distributed bearing area around the cone andthis has the tendency to stabilize the bit around the core.

- During rotation of the bit the circumferentially extending teeth onthe rollers have the tendency to cause the rollers to track on theteeth. However, as the rotation of the bit is restricted to a horizontalplane or substantially so, due to the limited progress of the bitdownwardly through the formation, the rollers are prevented fromtracking and effectively scariiy the sides of the cone. Although the topof the cone on the core is very near the center of rotation of the bitthe design is such that the teeth on the tops of the rollers move freelythereon with considerable travel so as to cause the very center of thecore to be efiectively scarifled and broken up so that there is neverany danger of a hard core forming on which the bit might ride.

From the above described construction it will be appreciated that anovel and advantageous core breaker for bits is provided which willcompletely and continuously break up and scarify the core left by thebit as the bit rotates. The rollers each provide a long length 01'cutting edge over which the wear is evenly distributed.

Various changes may be made in the details of construction withoutdeparting from the spirit or scope of the invention as described in theappended claims.

I claim:

1. A bit having a core breaker comprising a. roller having teeth formedthereon, said roller being rotatable about an axis which is upwardlyand-inwardly inclined to the axis of the bit and which is disposedotherwise than in a plane radial of the bit.

2. A bit having a core breaker comprising a roller havingcircumierentially extending teeth formed thereon, said roller beingrotatable about an axis which is inclined to the axis of the bit andwhich is disposed otherwise than in a plane radial of the bit. 5

3. A bit having a core breaker comprising a roller having teeth i'ormedthereon, said roller being rotatable about an axis which is inclined tothe axis of the bit and which is disposed otherwise than in a. planeradial of the bit, the roller 10 being of generally hyperboloidal shape.

4. A bit having a core breaker comprising a roller havingcircumferentially extending teeth formed thereon, said roller beingrotatable about an axis which is inclined to the axis of the bit 18 andwhich is disposed otherwise than in a plane radial of the bit, theroller being of generally hyperboloidal shape.

5. A bit having a core breaker comprising rollers, said rollers beingrotatable about axes which 20 are upwardly and inwardly inclined anddisposed in planes which are non-radial to the axis of the bit andhaving teeth formed thereon so that on rolling about the core the teethwill scarity the sides of the core.

6. A bit having a core breaker comprising rollers, said rollers beingrotatable about axes which are upwardly and inwardly inclined and havingteeth formed thereon so that on rolling about the core the teeth willscarify the sides of the $0 core, said rollers being of generallyhyperboloidal shape.

7. A bit having a core breaker comprising rollers mounted for rotationon the bit about axes which are upwardly and inwardly inclined and SQwhich are arranged otherwise than in planes radial of the bit, saidcutters having circumferentially extending teeth formed thereon andbeing of generally hyperboloidal shape.

8. A bit having cutting edges on its bottom and 40 a hollow center, corebreaker rollers disposed in the hollow center, and pins extendingthrough the rollers onwhich the rollers rotate, said pins extendingupwardly and inwardly in planes other than radial of the bit.

9. A bit having cutting edges on its bottom and a hollow center, corebreaker rollers disposed in the hollow center, and pins extendingthrough the rollers on which the rollers rotate, said pins extendingupwardly and inwardly in planes other 5 than radial oi the bit, therollers being provided with circumierentially extending teeth and beingof generally hyperboloidal shape.

o'rro namma.

